The IXI was the world's first

digital audio player A portable media player (PMP) (also including the related digital audio player (DAP)) is a portable consumer electronics device capable of storing and playing digital media such as audio, images, and video files. The data is typically stored o ...

. It was invented by Kane Kramer in 1979. In 1981 Kramer filed for a UK patent. UK patent 2115996 was issued in 1985, and U.S. Patent 4,667,088 was issued in 1987. In 1988 Kramer's failure to raise the £60,000 required to renew the patent resulted in the patent entering the public domain, but he is still the owner of the designs. IXI was around the size of a

credit card A credit card is a payment card issued to users (cardholders) to enable the cardholder to pay a merchant for goods and services based on the cardholder's accrued debt (i.e., promise to the card issuer to pay them for the amounts plus the o ...

and had a

LCD A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but in ...

screen and navigation and volume buttons. Four

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and software programming. A prototype is generally used to ...

models were built and a pre-production model went on sale at the APRS exhibition at

Earls Court Earl's Court is a district of Kensington in the Royal Borough of Kensington and Chelsea in West London, bordering the rail tracks of the West London line and District line that separate it from the ancient borough of Fulham to the west, the ...

in London, in October 1986.

References

{{reflist
Original investor's report on the IXI from 1979 (PDF) Format
Digital audio players Portable media players Portable audio players